A majority of mobile devices may operate under DC (direct current) regulated voltage supply. These devices may shut down or malfunction if the voltage provided by a power source varies, which may often occur when the power source is a photovoltaic (PV, e.g., solar) panel or other type of energy harvester. In a case where a mobile device is connected to a power source that supplies insufficient power or unregulated voltage, the mobile device may run into an unstable operation state, or, power oscillation.